Apparent listings cultivated from Steam's Content Description Record database show a handful of unannounced titles and PC ports bound for Steam, including versions of Mortal Kombat, Skulls of the Shogun and Pinball FX 2.
While the Steam CDR database manages to keep titles of unannounced titles well-hidden (with names like "ValveTestApp217140"), achievement data and images scraped from Steam and SteamDB — unearthed by a handful of NeoGAF forum members — reveals content for certain Steam games not currently listed for Valve's platform: Deadpool, Mortal Kombat, and Skulls of the Shogun.
Other listings point to more speculative but surprising releases, including possible listings for The King of Fighters XIII, Castle of Illusion and Strider. Art for a rumored Strider game was discovered earlier this year on Xbox.com and ratings for Castle of Illusion have been issued by international ratings board.
Publisher Activision confirmed a release of Deadpool for PC earlier this month.
In February, a similar excavation of the Steam database turned up listings for many unannounced Steam games, including Dyad and Fez, titles that were later officially confirmed.
Polygon has reached out to developers and publishers of the above games and will update with any new information.